Yes, "newer alloys" are better.
Tin whiskers can appear before your eyes. I've recently seen a whisker grow between two tin plated component leads while I watched (under a high power microscope).
While I use new CuAgSn solders, many of the "RoHsS complant" parts I buy use pure tin finishes on the leads and there are no other finishes available yet.
Classic Tin/Lead solders producted joints that were easy to visually inspect - the shape and surface texture of a good joint were fairly unique. Modern non-leaded solders produce a variety of lumpy grey results even when carefully applied.
Aiding an abetting the RoHS issues are the use of fluxes that are easily cleaned without CFCs. Old school rosin based fluxes worked well and left beautiful joints - but were nearly impossible to clearn off without CFC based solvents.